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2019-11-27 20:49:56 -0500 marked best answer Is there a way to read from a text or yaml file and pass its data to <arg> tag?

Just like rosparam that take yaml file as a parameter, I want to know if there is a way to read text or yaml file that contains parameters and pass the parameters to any attributes of the <arg> tag (e.g. value, default).

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2019-05-20 02:02:26 -0500 marked best answer is there a way to run the ROS code of machine A from machine B using serial communication?

Here is my machine setup. I have Jetson TX1 connected to raspberry pi, and each machine has a set of ROS-based codes. They are connected using the ttl-to-USB converter, and I checked that the connection was made using the standard pyserial library.

My question here is how I can use ROS to let them still get connected. The tutorial said that I need to have some kind of embedded linux development environment to write the code for the pi board on jetson and download the code to the pi board. But that's far beyond what I can do now, and I would like to come up with other ways to enable the serial communication, while the codes I wrote for both machines stay intact. I'm thinking of utilizing launch files (the launch files from the jetson tx1 calls serial-related libraries, which would call the ROS nodes written on the pi board). Please let me know if my theory is correct.

Thank you.

2019-05-20 02:01:35 -0500 marked best answer what kind of interface will it be if I use Ethernet-to-USB adapter to connect raspberry pi and Jetson?

This may be a general question, but I want to know what type of interface will an Ethnet-to-USB connection make on both a server side and a client side. I think that on the server side, whose port is USB, it has to be a serial interface, but I'm not sure about the client side whose Ethernet will be connected. And has this connection ever been used in the ROS application? I appreciate for anybody who knows well about this issue.

2019-05-20 01:52:28 -0500 marked best answer how can I create connections among three linux-based machines?

I have a launch file that basically connects a Jetson TX1 and a Raspberry Pi 3 witha ubuntu host machine. And I need to configure all three machines such that, when roscore runs in the host, it will make connections to the other two boards.

As far as hardware setup is concerned, there is an ethernet-based connection between my linux desktop (ubuntu 14.04) and the jetson tx1 (ubuntu 16.04). The raspberry pi 3 is connected to the jetson board via the USB-3.0-to-Ethernet adapter (AX11789).

Following the hardware setup, the software setup is done. At first, the /etc/network/interface file in my desktop is edited as follows:

auto eth0
iface eth0 iface static
address 192.168.1.42
netmask 255.255.255.0
gateway 192.168.1.26

Then in my jetson,

auto eth0
iface eth0 inet static
address 192.168.1.26
netmask 255.255.255.0

Because it seems correct that the jetson be configured as a gateway (router), the ip address of the jetson should be used as a gateway address in both the desktop and the pi board. So in the pi board,

auto eth0
iface eth0 inet static
address 192.168.1.102
netmask 255.255.255.0
gateway 192.168.1.26

After this, the ping requests between the desktop and the jetson as well as between the jetson and the pi work perfectly, but the ping request between the desktop and the pi board does not work, stating Ping from 192.168.1.102: Destination host unreachable.

Is there any critical information or step I am missing in this case? It may probably be due to the configuration with the Ethernet-to-usb adapter, but I'm not 100% certain about this.

2019-05-20 01:14:02 -0500 marked best answer is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

For image, I know that the Image Topic must be of type sensor_msgs::Image, but is there any feature in Rviz that would subscribe to any topic whose message type is sensor_msgs::ImagePtr?


Edit: @gvdhoorn I have ELP Camera usb-connected to Jetson TX1, and there is the package that publishes the video feed. And I want my laptop, which is connected to the Jetson via Ethernet crossover cable, to subscribe the video feed data (whether it is sensor_msgs::Image or sensor_msgs::ImagePtr) through Rviz. My old code published the data of type sensor_msgs::Image but for some reason, Rviz stopped when I added the topic for video feed, and I had to restart it. Any techniques as to how I should handle this?

2019-04-08 01:21:26 -0500 marked best answer how to start rostest file on startup?

Has anybody implemented the rostest file that would be launched on startup? All I did now was to type the command make run_tests in the build folder of the workspace manually. I want the file to be automatically run when my machine boots up. Any help would be appreciated, and let me know if you need any details from me.

2019-04-08 01:13:27 -0500 marked best answer Has anybody implemented rosserial_client-based node in Raspberry Pi?

I'm using the pi board as a client board as if it were an Arduino board connected to PC/laptop, and I'm wondering if anybody has ever done that. If so, could you tell me what libraries you used it?

With regards to rosserial_embeddedlinux, I need to download the development environment in my server-side host, which is Jetson, and in most of the cases IDEs are not able to be installed in Jetson platform. So I would rather write the implementation code for Hardware class (wiki.ros.org/rosserial_client/Tutorials/Adding Support for New Hardware) so that the rosserial-based connection for Raspberry Pi is established. Could anybody please help me with this?

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2019-03-01 12:42:59 -0500 marked best answer how to automatically launch all ros nodes in multiple machines?

In my project, there are two main computing boards connected to a laptop. The laptop has a master ROS server, and the boards have slave servers. What I want to accomplish is that when boards are turned on, they would automatically launch their nodes while still maintaining the connection to the laptop.

So far I only made a roslaunch file in a host laptop, a file that contains information about machines and nodes to run. And I installed robot_upstart in the host so that ros server as well as the nodes written in the host can be run at startup. So If I want the same thing to happen to the two boards while the three machines stay connected to each other, what should I do?

Thanks for any help.

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2018-04-27 14:15:22 -0500 marked best answer for uwsim, how can I create two currents?

For my project, I would like to make my scene in which two currents are generated in different directions. I thought having two oceanState tags would get this done, but it gave me an error.

Any method or resource I should know? Thanks.

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2018-04-13 13:01:36 -0500 marked best answer how to echo custom-defined message remotely?

There are two machines, A and B, connected via Ethernet cable, and their connections are established. One of the ROS package implemented at the machine A has custom messages, and I would like it to be read at the machine B by using the command rostopic echo <topic-name>.

When I typed the command, I got the following error message.

ERROR: Cannot load message class for [<message-name>]. Are your messages built?

Does this mean that I have to build the custom message at the machine B as well? If so, how?

2018-03-30 12:58:05 -0500 commented question Rviz's transport Hint only has raw

Yes. And I verified that using the command rosrun image_transport list_transports

2018-03-30 12:40:35 -0500 commented answer is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

Thanks for your help. I removed the source from my catkin project and instead installed using commands. By the way, ros-

2018-03-30 11:56:48 -0500 commented question Rviz's transport Hint only has raw

I looked at #q263977 and no solution was found yet. Transport Hint only has raw, and it seems that I have to figure out

2018-03-30 11:45:52 -0500 answered a question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

I found the solution. The image_transport package was not fully installed; the plugins for type compressed and theora we

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2018-03-27 11:20:49 -0500 commented question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

I thought so. But I guess, unlike mine, most camera-related projects I have examined are based on a single machine, so n

2018-03-27 11:04:14 -0500 commented question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

I tried to find any example projects like that, and I couldn't. I tried to do this myself using all available sources, a

2018-03-27 11:02:12 -0500 commented question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

I see. Thanks for your help. So my next question is whether there has ever been a project that remotely transmits video

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2018-03-27 10:07:26 -0500 answered a question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

@gvdhoorn I have ELP Camera usb-connected to Jetson TX1, and there is the package that publishes the video feed. And I w

2018-03-26 16:24:45 -0500 asked a question Rviz's transport Hint only has raw

Rviz's transport Hint only has raw The system has theora, compressed, and compressedDepth, but they are not shown as alt

2018-03-26 16:22:30 -0500 asked a question is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr?

is there a way for rviz to subscribe to topic of message typ sensor_msgs::ImagePtr? For image, I know that the Image Top

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2018-03-22 12:22:51 -0500 asked a question how to echo custom-defined message remotely?

how to echo custom-defined message remotely? There are two machines, A and B, connected via Ethernet cable, and their co

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